We report a case of 67-year-old woman with systemic lupus erythematosus presenting hyporeninemic hypoaldosteronism. She admitted because of anasarca in March, 1990. She manifested nephrotic syndrome, and hyperkalemic and hyperchloremic metabolic acidosis. The hyperkalemia was disproportionate to the degree of renal insufficiency. Basal levels of plasma renin activity and plasma aldosterone concentration were low. Renal tubular function studies revealed normal hydrogen ion secretion. Renal biopsy demonstrated diffuse proliferative lupus nephritis and prominent interstitial cell infiltration. There was no vasculitis of glomerular vascular poles. After treatment of lupus nephritis with prednisolone, levels of plasma renin activity and plasma aldosterone concectration were elevated. Hyperkalemia and metabolic acidosis were normalized and renal function improved. We conclude that the heperkalemia and metabolic acidosis could be attributed to hyporeninemic hypoaldosteronism.